(1) Field of the Invention
The present invention relates to a clutch release device for motorized cycles and, more particularly, to a clutch release device for chain-driven type motorized cycles such as motor-cycles and motorized tricycles.
(2) Description of Relevant Art
Chain-driven type motorized cycles such as motorcycles and motorized tricycles generally include a power transmission mechanism composed of a primary transmission mechanism, a clutch, a speed change gearing, etc. and integrally formed with an engine, in which the speed change gearing has a main shaft and a counter shaft both arranged to extend substantially transversely of the cycle together with a crankshaft of the engine. The main shaft is provided at either end thereof with the clutch of a friction type, and the counter shaft is provided at its the opposite end thereof with a sprocket mechanism for driving a rear wheel driving chain.
As a device for releasing a friction type clutch in such power transmission mechanism, there has been proposed a clutch release device of a hydraulic type in which a push rod member arranged to extend through a tubular main shaft is connected at either end thereof with a pressure plate and provided at the other end thereof with a hydraulic cylinder acting In such clutch release device, however, when it is desired to arrange the hydraulic cylinder on the outside of a crank case supporting the main shaft and a counter shaft at both ends thereof, whereas the hydraulic cylinder has a substantially predetermined volume and the space between the main shaft and the counter shaft is relatively narrow in addition to the requirement for a chain to be stretched near either lateral side of a rear wheel, the hydraulic cylinder is necessarily arranged in a position adjacent a driving sprocket.
When considering the durability of the chain, it is desirable that the sprocket have a relatively large diameter. However, because the hydraulic cylinder is arranged as described above, it is impossible to incorporate a large diameter sprocket.
The present invention effectively overcomes the foregoing problems attendant a conventional clutch release device for motorized cycles.